The storage of ware potatoes in permanent buildings II. The temperature of unventilated stacks of potatoes

Abstract

1. Under normal English storage conditions, the heat production of mature potatoes drops rapidly from a value of probably about 150 b.th.u./ton/hr. immediately after harvest to about 30–50 b.th.u./ton/hr. Sprouting is accompanied by an increase in the rate of heat production. The initial heat production of immature potatoes may be of the order of 250 b.th.u./ton/hr.2. As a result of the production of heat, the temperatures in stacks of potatoes will tend to rise to levels above that of the outside air which are just sufficient to cause the convection and conduction necessary to remove the metabolic heat as fast as it is produced.3. The difference in temperature between the potatoes and the ambient air is a function of the heat production of the potatoes and of the height of the stack, and is practically independent of its other dimensions if these exceed twice the height. Under average conditions during the middle of the storage season, and for heights of storage of from about 6 to 12 ft. it may be taken as a rough practical guide that the average and maximum temperatures of the potatoes will tend to exceed the average temperature of the store air by about 2/3 and 1° F. respectively for every foot of height.4. Overheating is possible at both the beginning and end of the storage season, when heat production is high and the outside temperatures also possibly high. In general it is safe to store unventilated potatoes to a height of about 6 ft. if they are mature, though if they are harvested with a great deal of earth late storage should not be attempted. If there is no intention of storing late, and the potatoes are fairly clean, storage to aheight of 12 ft. may be permissible. Immature potatoes should not be stored to a height of more than 3 ft.

CFD simulation of effects of operating parameters and product on heat transfer and moisture loss in the stack of bagged potatoes

“…The effect of bulk porosity in the range of 0.3-0.4 (particularly 0.35-0.4) is of commercial interest as because, the potatoes in bag or bulk have bulk porosity of the order of 0.4 (Burton, Mann, & Wager, 1955;Xu, Burfoot, & Huxtable, 2002). When the bags of potatoes are placed one above another in the form of a stack, the bags near the bottom end compressed due to the load of the upper bags and hence the porosity in the lower bags decrease.…”

“…(Chourasia & Goswami, 2001). It is reported that the rate of metabolic heat production from the immature potatoes could be about 80 W/m 3 at 10°C (as high as 110 W/m 3 at 22°C) in comparison to 48 W/m 3 from mature tubers at the same temperature (Burton et al, 1955). However, during the storage period the normal range varies from 10 to 16 W/m 3 .…”

“…The effect of heat generation was comparatively more pronounced at lower range (10-30 W/m 3 ) than at higher one (50-70). The lower range is also important from the point of view of the long-term storage of potato as because the generation of heat in potato during the storage period falls in this range only (Burton et al, 1955).…”

Sprouting of Potatoes: Compositional Changes in Light and Dark

“…Treadway et al (1949) found that the sprouts were higher in reducing sugars and lower in starch than the whole tuber, and Mondy and Mattick (1969) observed that sprouts contained significantly more crude lipid and phospholipid than either the cortex or pith sections of the tuber. Sprouting is associated with increased respiration (Burton et al 1955) and amylase activity (Bruinsma 1962). Although Cotrufo (1958) found no large changes in amino acid content of the internal tissues of potatoes at the breaking of the rest period, Ashford and Levitt (1965) observed that the proteinhonprotein nitrogen ratio was higher in the cortex than in the pith tissue both at 3°C and at 26OC storage.…”

The Two Point Temperature Measurement—A Method to Determine the Rate of Respiration in a Potato Pile

“…In most cases, the carbon dioxide production has been measured (Burton et al, 1955;Burton, 1966;Hunter, 1976). Many of the determinations have been carried out in laboratories.…”